diff --git a/scripts/setup-vm.sh b/scripts/setup-vm.sh
index 641d46b..eec2e14 100755
--- a/scripts/setup-vm.sh
+++ b/scripts/setup-vm.sh
@@ -637,8 +637,11 @@ if conformant and E["CONVERT"] == "1":
         if "device='disk'" not in d or ("bus='nvme'" in d and "<serial>" in d):
             return d
         d = re.sub(r"<target dev='([^']*)' bus='(virtio|sata|scsi)'/>", r"<target dev='\1' bus='nvme'/>", d)
+        # cache='none' is O_DIRECT: on btrfs the guest can change a page while the
+        # write is in flight, so the stored checksum never matches and later reads
+        # fail with EIO. Buffered writes hand the filesystem a stable page.
         d = re.sub(r"<driver name='qemu' type='([^']*)'[^/]*/>",
-                   r"<driver name='qemu' type='\1' cache='none' io='native' discard='unmap'/>", d)
+                   r"<driver name='qemu' type='\1' cache='writeback' io='threads' discard='unmap'/>", d)
         d = re.sub(r"\s*<address type='(pci|drive)'[^/]*/>", "", d)
         if "<serial>" not in d:
             serial = E["NVME_SERIAL"] if n[0] == 0 else E["NVME_SERIAL"][:-1] + "0123456789ABCDEF"[n[0] % 16]
@@ -824,7 +827,7 @@ if [ "$PROFILE" = full ]; then
 fi
 
 if [ ! -e /usr/lib/udev/rules.d/99-vfio-native-vnet-offload.rules ] && [ ! -e /etc/udev/rules.d/99-vfio-native-vnet-offload.rules ]; then
-    echo "NOTE: the e1000e offload udev rule is not installed. SSH into the guest will fail with"
+    echo "NOTE: the NIC offload udev rule is not installed. SSH into the guest will fail with"
     echo "      'Corrupted MAC on input' until it is:"
     echo "      sudo install -Dm644 $SELF/scripts/99-vfio-native-vnet-offload.rules /etc/udev/rules.d/ && sudo udevadm control --reload-rules"
 fi